Materials Literature
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The enhancement of photoluminescence emission from silicon quantum dots in the near field of cylindrical silver particles has been calculated using finite integration techniques. This computational method permitted a quantitative examination of the plasmon resonance frequencies and locally enhanced fields surrounding…
High-level electronic structure calculations have been used to map out the relevant portions of the potential energy surfaces for the release of H2 from dimers of ammonia borane, BH3NH3 (AB). Using the correlation-consistent aug-cc-pVTZ basis set at the second-order perturbation MP2 level, geometries of stationary poi…
The design and synthesis of the first examples of AB4 and AB5 dendritic building blocks with complex architecture are reported. Structural and retrostructural analysis of supramolecular dendrimers self-assembled from hybrid dendrons based on different combinations of AB4 and AB5 building blocks with AB2 and AB3 benzyl…
X-ray damage to protein crystals is often assessed on the basis of the degradation of diffraction intensity, yet this measure is not sensitive to the rapid changes that occur at photosensitive groups such as the active sites of metalloproteins. Here, X-ray absorption spectroscopy is used to study the X-ray dose-depend…
We prepared a novel oligomeric electrolyte that acts as a multifunctional gelator. The gelator has the following notable characteristics: (1) facile preparation in one pot involving condensation and subsequent intermolecular quaternization reaction; (2) tunable solubility to apply to various solvents (e.g., organic, a…
In this work, a method of pseudospherical architecture for materials with noncubic crystal systems has been demonstrated by coupling two porous mesocrystalline hemispheres. This synthetic method promises new possibilities of compositional control, property tuning, and structural organization for hybrid inorganic−organ…
Abstract In order to identify new oxide ion‐conducting materials in the ceria family of oxides, the unique effect of co‐doping is explored and a novel series of Ce 0.8 Sm 0.2– x Ca x O 2–δ compositions is identified that have enhanced properties compared to the single‐doped Ce 0.8 Sm 0.2 O 1.9 and Ce 0.8 Ca 0.2 O 1.9…
Macromolecules with defined nanosizes--nanoglobules--were synthesized and characterized as novel drug carriers with precise molecular architectures. Poly-L-lysine dendrimers with a cubic octa(3-aminopropyl)silsesquioxane (OAS) core, (L-lysine 8-OAS, (L-lysine) 16-(L-lysine) 8-OAS, (L-lysine) 32-(L-lysine) 16-(L-lysine…
We report on a theoretical derivation of the electronic dielectric response of semiconductor nanocrystals using a tight-binding framework. Extending to the nanoscale the Hanke and Sham approach [Phys. Rev. B 12, 4501 (1975)] developed for bulk semiconductors, we show how local field effects can be included in the stud…
Within many-body perturbation theory we apply vertex corrections to various closed-shell atoms and to jellium, using a local approximation for the vertex consistent with starting the many-body perturbation theory from a DFT-LDA Green's function. The vertex appears in two places -- in the screened Coulomb interaction,…
The effects of isolated residual-gas adsorbates on the local electronic structure of the Dy(0001) surface were spatially mapped by scanning tunneling microscopy and spectroscopy at 12 K. Less than 15 A away from an adsorbate, a strong reduction of the intensity and a significant increase of the width of the majority c…
The electron doped manganite system, Bi0.125Ca0.875MnO3, exhibits large bulk magnetization of unknown origin. To select amongst possible magnetic ordering models, we have conducted temperature and magnetic field dependent small-angle neutron scattering measurements. Nontrivial spin structure has been revealed. Ferroma…
Spin transport equations in a non-homogeneous ferromagnet are derived in the limit where the sd exchange coupling between the electrons in the conduction band and those in the d band is dominant. It is shown that spin diffusion in ferromagnets assumes a tensor form. The diagonal terms are renormalized with respect to…
We demonstrate that the interaction between excitons and a sea of incoherent electrons does not preclude excitons dressing by light. We investigate the role of exciton-electron scattering in the light dressing by measuring the dynamical absorption spectrum of a modulation-doped CdTe quantum well, which shows a clear e…
${\mathrm{Ti}}_{50}{\mathrm{Pd}}_{50\ensuremath{-}x}{\mathrm{Cr}}_{x}$ is a high-temperature shape-memory alloy with a martensitic transformation temperature strongly dependent on the Cr composition. Prior to the transformation, a premartensitic phase is present with an incommensurate modulated cubic lattice with wave…
Abstract Semiconductor ZnS with novel and complex 3D architectures such as nanorods (or nanowires) networks, urchinlike nanosturctures, nearly monodisperse nanospheres self‐assembled from nanorods and 1D nanostructures (rods and wires) had been synthesized in a binary solution by controlling the reaction conditions, s…
Abstract We report on the application of mixed polymer brushes to the reversible in situ switching colloidal systems (suspensions of responsive 200 nm in diameter particles in individual solvents and immiscible liquids). We used mixed copolymer brushes to fabricate responsive nanoparticles and employed the particles t…
The competition between α, β, and γ polymorphs has been studied in a β-nucleated metallocenic isotactic polypropylene, iPP, as a function of the cooling rate and of the isothermal crystallization temperature, by performing X-ray diffraction and DSC experiments. It was found that the addition of a 1% by weight of a typ…
Cleaved and polished surfaces of CaCu$_3$Ti$_4$O$_{12}$ ceramics have been investigated by x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectroscopy (EDX), respectively. While EDX technique shows the identical CaCu$_3$Ti$_4$O$_{12}$ stoichiometry for the two surfaces, XPS indicates that the cleav…
UNLABELLED: This study evaluates the quantitative biodistribution of commercially available CdSe quantum dots (QD) in mice. METHODS: (64)Cu-Labeled 800- or 525-nm emission wavelength QD (21- or 12-nm diameter), with or without 2,000 MW (molecular weight) polyethylene glycol (PEG), were injected intravenously into mice…